Looks like life on earth survived to this day!
Apparently, the CO2 concentration in the atmosphere fluctuates due to natural causes for millions of years!
Always remember: CO2 is a life essential trace gas! Global Warming is a hoax and Climate Change is a religion!
"A previously untapped source of data sheds new light on the climate of the early Earth: fossilized dinosaur teeth show that the atmosphere during the Mesozoic era, between 252 and 66 million years ago, contained far more carbon dioxide than it does today. ...
In addition, the researchers found that total photosynthesis from plants around the world was twice as high as it is today. This probably contributed to the dynamic climate during the time of the dinosaurs. ...
In the late Jurassic period, around 150 million years ago, the air contained around four times as much carbon dioxide as it did before industrialization ...
And in the late Cretaceous period, around 73 to 66 million years ago, the level was three times as high as today. ..."
From the significance and abstract:
"Significance
Paleoclimate is closely linked to atmospheric pCO2. Quantifying ancient CO2 levels, however, is challenging. Air-breathing vertebrates respire air O2 and incorporate its isotope signature via body water into their hard tissues.
Fossil tooth enamel can thus serve as a robust time capsule for ancient air O2 isotope compositions. Air O2 has an 17O-anomaly that increases with increasing atmospheric pCO2 and decreases with increasing gross primary productivity (GPP). Therefore, paleo-pCO2 or paleo-GPP, respectively, can be determined by oxygen isotope measurements of fossil tooth enamel.
Here, we reconstruct Mesozoic paleo-pCO2 levels from the triple oxygen isotope composition of dinosaur teeth and obtain paleo-pCO2 levels 2.5 to 4 times higher than preindustrial values. In addition, changes in the 17O-anomaly could also point to substantial fluctuations in GPP of the biosphere.
Abstract
Air-breathing vertebrates incorporate a fraction of isotopically anomalous air O2 in their body water. The 17O isotope anomaly of air O2 (expressed as Δ’17Oair) is related to atmospheric CO2 concentrations (pCO2) and gross primary production (GPP).
Tooth enamel records the Δ’17O of body water and can thus preserve such paleo-pCO2 or paleo-GPP information over geological time periods.
Here, we demonstrate the potential of respective reconstructions of atmospheric pCO2 or GPP from the triple oxygen isotope composition of fossil dinosaur tooth enamel. The data from unaltered enamel samples, along with an assumed modern GPPt/GPP0 ratio of 1 for the Mesozoic, suggest a mean Late Jurassic pCO2 = 1,200 ± 150 ppmv and Late Cretaceous pCO2 = 750 ± 200 ppmv. These estimates are in good agreement with other pCO2 proxy data for the same time intervals. When utilizing a pCO2 inferred from other proxies, tooth enamel Δ’17OPO4 may also serve as a proxy for GPP. Using published pCO2 data, we reconstructed GPPt/GPP0 ratios with 1.20 ± 0.17 for the Late Jurassic and 2.24 ± 0.96 for the Late Cretaceous, which would imply a 20 to 120% higher GPP in the Mesozoic than today. Overall, triple oxygen isotope analysis of fossil teeth of terrestrial amniotes can provide insights into past atmospheric greenhouse gas content and global primary productivity."
Press release: Dinosaur teeth give glimpse of early Earth’s climate (original news release)
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